In micro-electromechanical system (MEMS) devices that have exposed electrodes, the hermetic sealing (bonding) of glass-to-glass (“G/G”), glass-to-silicon (“G/S”) and silicon-to-silicon (“S/S”) is very difficult to accomplish. Examples of applications that have such exposed electrodes include organic light-emitting diodes (OLED) and digital light processing (DLP™) packaging technologies, among others. In a very simple view of DLP devices, the devices comprise a housing, a mirror or an array of mirrors and/or other functional elements within the housing, and a glass window hermetically sealed to the housing. Hermetically sealing such packaging is quite difficult when there are temperature restraints; for example, the necessity of using temperatures of less than 250° C. and especially less than 150° C. to effect the seal. In such instances the use of lasers for localized heating to make the seal cannot be used when the electrodes are exposed because the localized heating can weaker or destroy electrode bonding. In cases where hermetic seal bonding temperature is not a problem, a dielectric material layer can be deposited over the electrodes and an indium-based solder is then used in conjunction with lasers to affect hermetic sealing. However, this method works only for low voltage and low frequency applications; cross-talk between electrodes being a major problem. Examples of the packaging of DLP devices can be found in a number of patent publications including U.S. Pat. Nos. 6,667,837; 6,745,449; 6,586,831; 6,624,921; 6,455,927; and 6,627,814.
In DLP packaging application the MEMS' mirror or mirror array, the heart of the DLP, must be hermetically packaged in a housing having a glass window to permit the entry and exit of light. Hermetic sealing is necessary to prevent contamination of the mirror, for example by dust particles, during operation of the equipment containing the DLP. In many existing processes Kovar® 7056 is used as the sealing material, bonding the glass window to the housing containing the DLP mirror or array of mirrors. While this material produces a good seal, the process used to affect bonding and sealing is both slow and labor intensive, resulting in high costs. As a result, it is highly desirable to find a different method and/or materials that can be used to hermetically seal devices such as OLED and DLP devices. The present invention discloses a novel method for effecting a hermetic seal in OLED, DLP and other devices requiring a hermetic seal. In addition to sealing DLP devices the process of the present invention can also be used in other devices such as DLP control devices that do not contain a glass window and in other optical, opto-electronic and electronic devices.